Membrane separation of water from aqueous mixtures

Abstract

Water is separated from aqueous mixtures of organic and inorganic compounds by contacting the aqueous mixture against a first surface of a polymeric membrane selectively permeable to water, contacting the second surface of the membrane with a sweep liquid having a thermally dependent water miscibility, withdrawing a water enriched miscible sweep liquid from the second surface, and forming a water rich phase and a sweep liquid phase through the thermal adjustment of the withdrawn water-enriched miscible sweep liquid. The water miscible sweep liquid is selected from those liquids having normal or inverted thermal miscibility for water and which allow for the thermal separation of a water-rich liquid phase.

What is claimed is: 
     
       1. A process for the liquid to liquid, one phase separation of water from aqueous mixtures, comprising: (a) contacting an aqueous mixture with the first surface of an organic polymeric membrane selectively permeable to water; (b) permeating a portion of the water from the aqueous mixture into and through the membrane; (c) contacting a second and opposite surface of the membrane with a water-miscible sweep liquid comprised of phenol; (d) withdrawing a water-enriched, miscible phase from the second membrane surface; (e) thermally adjusting the water-enriched miscible phase to a temperature beyond the water miscibility temperature of the phenol; and (f) forming two liquid phases comprised of the water rich phase and the phenol rich phase.